| |
Records |
Links |
|
Author |
Haas, C.; Thomas, D.N.; Bareiss, J. |
|
| |
Title |
Surface properties and processes of perennial Antarctic sea ice in summer |
Type |
Journal Article |
| |
Year |
2001 |
Publication |
Journal of Glaciology |
Abbreviated Journal |
J Glaciol |
|
| |
Volume |
47 |
Issue |
159 |
Pages  |
613-625 |
|
| |
Keywords |
|
|
| |
Abstract |
Ice-core and snow data from the Amundsen, Bellingshausen and Weddell Seas, Antarctica, show that the formation of superimposed ice and the development of seawater-filled gap layers with high algal standing stocks is typical of the perennial sea ice in summer. The coarse-grained and dense snow had salinities mostly below 0.1ppt. A layer of fresh superimposed ice had a mean thickness of 0.04-0.12 m. Gap layers 0.04-0.08 m thick extended downwards from 0.02 to 0.14 m below the water level. These gaps were populated by diatom standing stocks up to 439 ?g L?¹ chlorophyll a. We propose a comprehensive heuristic model of summer processes, where warming and the reversal of temperature gradients cause major transformations in snow and ice properties. The warming also causes the reopening of incompletely frozen slush layers caused by flood-freeze cycles during winter. Alternatively, superimposed ice forms at the cold interface between snow and slush in the case of flooding with negative freeboard. Combined, these explain the initial formation of gap layers by abiotic means alone. The upward growth of superimposed ice above the water level competes with a steady submergence of floes due to bottom and internal melting and accumulation of snow. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
International Glaciological Society |
Place of Publication |
Cambridge |
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0022-1430 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
IPØ/Tvärrminne |
Approved |
no |
|
| |
Call Number |
refbase @ admin @ Haas++2001 |
Serial |
742 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Mock, T.; Thomas, D.N. |
|
| |
Title |
Recent advances in sea-ice microbiology |
Type |
Journal Article |
| |
Year |
2005 |
Publication |
Environmental Microbiology |
Abbreviated Journal |
Environ Microbiol |
|
| |
Volume |
7 |
Issue |
5 |
Pages |
605-619 |
|
| |
Keywords |
|
|
| |
Abstract |
Over the past 50 years there has been much effort invested in the investigation of the ecology of sea ice. Sea ice is an ephemeral feature of the Arctic and Southern Oceans and smaller water bodies such as the Baltic and Caspian Seas. The semisolid ice matrix provides a range of habitats in which a diverse range of microbial organisms thrive. In the past 5 years there has been considerable steps forward in sea-ice research, in particular regarding the analysis of sea-ice microstructure and the investigation of the diversity and adaptation of microbial communities. These studies include: (i) controlled simulated and in situ studies on a micrometer scale to unravel the dynamic of the microhabitat with consequences for the organisms; (ii) the introduction of molecular approaches to uncover the diversity of uncultured still unknown microorganisms; and (iii) studies into the molecular adaptation of selected model organisms to the extreme environment. This minireview presents some of the most recent findings from sea-ice studies within the framework of these aims. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
Blackwell Publishing, Inc. |
Place of Publication |
Oxford |
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1462-2912 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
Minireview |
Approved |
no |
|
| |
Call Number |
refbase @ admin @ Mock+Thomas2005 |
Serial |
750 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Schnack-Schiel, S.B.; Dieckmann, G.S.; Kattner, G.; Thomas, D.N. |
|
| |
Title |
Copepods in summer platelet ice in the eastern Weddell Sea, Antarctica |
Type |
Journal Article |
| |
Year |
2004 |
Publication |
Polar Biology |
Abbreviated Journal |
Polar Biol |
|
| |
Volume |
27 |
Issue |
8 |
Pages |
502-506 |
|
| |
Keywords |
|
|
| |
Abstract |
Copepods in platelet-ice layers underlying fast ice and in the water column below were studied at Drescher Inlet, eastern Weddell Sea in February 1998. Three copepod species were found: Drescheriella glacialis and Paralabidocera antarctica occurred in platelet-ice layers, while Stephos longipes was only present in the water column. The distribution of all species varied considerably between station and depth. D. glacialis dominated the platelet-ice community and occurred at all five platelet-ice sampling sites, except one, with numbers of up to 26 ind. l?¹. In contrast, P. antarctica was only found in low numbers (up to 2 ind. l?¹) at one site. The total copepod abundance in the platelet ice was not associated with algal biomass, although it was strongly correlated with high ammonium concentrations (up to 9 µM) in the interstitial water between the platelets. This is the first indirect evidence to support the hypothesis that zooplankton excretion can partly account for the high ammonium values often found in platelet-ice layers. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
Springer-Verlag |
Place of Publication |
Heidelberg |
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0722-4060 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
Short note |
Approved |
no |
|
| |
Call Number |
refbase @ admin @ Schnack-Schiel++2004 |
Serial |
752 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Thomas, D.N.; Kennedy, H.; Kattner, G.; Gerdes, D.; Gough, C.; Dieckmann, G.S. |
|
| |
Title |
Biogeochemistry of platelet ice: its influence on particle flux under fast ice in the Weddell Sea, Antarctica |
Type |
Journal Article |
| |
Year |
2001 |
Publication |
Polar Biology |
Abbreviated Journal |
Polar Biol |
|
| |
Volume |
24 |
Issue |
7 |
Pages |
486-496 |
|
| |
Keywords |
|
|
| |
Abstract |
An array of four sediment traps and one current meter was deployed under a well-developed platelet layer for 15 days in the Drescher Inlet in the Riiser Larsen ice shelf, in February 1998. Traps were deployed at 10 m (just under the platelet layer), 112 m (above the thermocline), 230 m (below thermocline) and 360 m (close to sea floor). There was a substantial flux of particulate organic material out of the platelet layer, although higher amounts were collected in the traps either side of the thermocline. Material collected was predominantly composed of faecal pellets containing diatom species growing within the platelet layer. The size classes of these pellets suggest they derive from protists grazing rather than from larger metazoans. Sediment trap material was analysed for particulate organic carbon/nitrogen/phosphorus (POC/PON/POP) and ?¹³CPOC (carbon isotopic composition of POC). These were compared with organic matter in the overlying platelet layer and the water column. In turn, the biogeochemistry of the platelet layer and water column was investigated and the organic matter characteristics related to inorganic nutrients (nitrate, nitrite, ammonium, silicate, phosphate), dissolved organic carbon/nitrogen (DOC/DON), pH, dissolved inorganic carbon (DIC), oxygen and ?¹³CDIC (carbon isotopic composition dissolved inorganic carbon). |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
Springer-Verlag |
Place of Publication |
Heidelberg |
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0722-4060 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
|
Approved |
no |
|
| |
Call Number |
refbase @ admin @ Thomas++2001_2 |
Serial |
762 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Arrigo, K.R.; Thomas, D.N. |
|
| |
Title |
Large scale importance of sea ice biology in the Southern Ocean |
Type |
Journal Article |
| |
Year |
2004 |
Publication |
Antarctic Science |
Abbreviated Journal |
Antarct Sci |
|
| |
Volume |
16 |
Issue |
4 |
Pages |
471-486 |
|
| |
Keywords |
algae; Antarctic; biogeochemistry; carbon cycle; primary production; Full Data Records |
|
| |
Abstract |
Despite being one of the largest biomes on earth, sea ice ecosystems have only received intensive study over the past 30 years. Sea ice is a unique habitat for assemblages of bacteria, algae, protists, and invertebrates that grow within a matrix dominated by strong gradients in temperature, salinity, nutrients, and UV and visible radiation. A suite of physiological adaptations allow these organisms to thrive in ice, where their enormous biomass makes them a fundamental component of polar ecosystems. Sea ice algae are an important energy and nutritional source for invertebrates such as juvenile krill, accounting for up to 25% of total annual primary production in ice-covered waters. The ability of ice algae to produce large amounts of UV absorbing compounds such as mycosporine-like amino acids makes them even more important to organisms like krill that can incorporate these sunscreens into their own tissues. Furthermore, the nutrient and light conditions in which sea ice algae thrive induce them to synthesize enhanced concentrations of polyunsaturated fatty acids, a vital constituent of the diet of grazing organisms, especially during winter. Finally, sea ice bacteria and algae have become the focus of biotechnology, and are being considered as proxies of possible life forms on ice-covered extraterrestrial systems. An analysis of how the balance between sea ice and pelagic production might change under a warming scenario indicates that when current levels of primary production and changes in the areas of sea ice habitats are taken into account, the expected 25% loss of sea ice over the next century would increase primary production in the Southern Ocean by approximately 10%, resulting in a slight negative feedback on climate warming. |
|
| |
Address |
|
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
Cambridge University Press |
Place of Publication |
Cambridge |
Editor |
|
|
| |
Language |
|
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
0954-1020 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
Review |
Approved |
no |
|
| |
Call Number |
refbase @ admin @ Arrigo+Thomas2004 |
Serial |
729 |
|
| Permanent link to this record |
